November 22, 2010

Thanksgiving blizzard ... but not for us

Nothing like a late-autumn blizzard at Thanksgiving to spice up the weather and travel forecast. Fortunately for Marylanders, all the excitement, for now, is far to our north and west.

AccuWeather.com is watching the arctic air spill into the mountain Northwest, and predicting blizzard conditions across the Dakotas and eastward to Michigan at midweek. That system will begin to affect the Great Lakes and the Northeast later in the week, AccuWeather.com said:

"Cold winds will follow the storm throughout the Great Lakes region on Thanksgiving and the interior Northeast into the weekend. The cold air blowing over the relatively warm lake waters may trigger the biggest episode of lake-effect snow since last winter."

So, if your Thanksgiving plans take you to Erie, Pa., or Buffalo, or Cleveland, or other points north and west, go prepared for wintry conditions and problematic driving late in the week.

Here in Central Maryland we shouldn't have to contend with any of that for the moment. The National Weather Service says we can expect these balmy 65-degree days to continue through Tuesday. Then the first of two cold fronts will pass through. The first, on Tuesday, could be heralded by a narrow band of showers.

Wednesday will be cooler after the frontal passage - in the 50s. But it will be sunny as high pressure builds in behind the front, and a fine day to travel if you must.

But that ridge of high pressure will move offshore pretty quickly, followed by another, stronger cold front out of the Ohio Valley. It may not get here until late on Thanksgiving Day, forecasters say. This one could bring some thunderstorms as it goes through. But we will only have to read about wintry weather to our north.

There's colder weather behind that front. Our weekend highs will stall out in the 40s with some gusty winds. But at least it will be sunny.

Beyond that, however, some forecasters are continuing to talk about the growing risk of some much colder, and perhaps snowy weather. While it won't get here during the long holiday weekend, as had once been feared, Eric the Red, at least, seems pretty confident that we'll be seeing some action early in December.

Eric, a professional forecaster from Baltimore, is watching as a "massive blocking high" over Greenland continues to form. This is the feature that tends to force the northern jet stream to loop southward into the Northeast, bringing us much colder weather. Add a storm to the mix and we could see snow. Last winter's blizzards involved such blocking highs - also called a negative phase of the Arctic Oscillation.

So, "the effects will not be immediate because there will be some combatting forces at play," Eric said. "Trust me on this: The blocking high will win this battle eventually ... it just might take a week."

Until that happens, he continues, "we'll be spared the full brunt of the arctic air that is poised to plunge south. But the models not only show the block holding on, they move it west into the jackpot-for-snow spot ... the Davis Strait [the narrow waterway betweeen Greenland and Baffin Island]... When the blocking highs move west and reach the Davis Strait, inevitably some sorta East Coast storm spins up ... sometimes too far offshore, but sometimes not (like last year). This particular high reaches the Davis Strait on or about Dec. 1. So the first week of December could get very, very interesting."

Snow on Dec. 5 again?Here's what Foot's Forecast has to say about the first days of December:

"December 4 - 8 in the along the east coast is the first period of potentially disturbing weather. Several long-range climate teleconnections that our team routine monitors continue to show strong signals this period may feature a particularly high-impact event along the eastern seaboard."

Comments

Thanks Frank! Love the updates. Don't know if I'm ready for snow already. But Eric sure seems confident that we'll see some precip next week. Gotta get the pellet stove all cleaned up and ready for the coming winter. Thanks again.

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Frank Roylance is a reporter for The Baltimore Sun. He came to Baltimore from New Bedford, Mass. in 1980 to join the old Evening Sun. He moved to the morning Sun when the papers merged in 1992, and has spent most of his time since covering science, including astronomy and the weather. One of The Baltimore Sun's first online Web logs, the Weather Blog debuted in October 2004. In June 2006 Frank also began writing comments on local weather and stargazing for The Baltimore Sun's print Weather Page. Frank also answers readers’ weather queries for the newspaper and the blog. Frank Roylance retired in October 2011. Maryland Weather is now being updated by members of The Baltimore Sun staff